Many self-heating products are emerging in the marketplace. The applications include products for food, beverages, and hand warmers. There are many areas such as disposable wipes where an unmet need exists is in the application of the technology. These applications, as well as others, require self-heating through the reaction of chemicals. The initiation and control of these reactions, retention and distribution of heat, and handling of materials are key issues. These issues are only partially handled for various products in the market. One key area not addressed in the market is a sustained modulation of heat.
In the initiation of these heating reactions, control of these reactions, retention and distribution of heat, and handling of materials are key issues that are partially handled for various products in the market. The temperature peak for a heating system is typically not to reach above 100° C., so that steam is not generated and pressures within the heating container do not increase significantly.
Many self-heating cans have dual chambers; an inner chamber that holds food or drink and the outer chamber houses chemicals that undergo the exothermic reaction. For example, a self-heating coffee marketed under the Wolfgang Puck name, was recently manufactured. The self-heating cans were activated by pushing a plastic button on the bottom, allowing water to flow into a sealed inner cone filled with quicklime, which is mostly calcium oxide, and heating the coffee to 145° F. in six to eight minutes. When the user wants to heat the contents of the can, they pull a ring on the can that breaks the barrier separating the chemicals in the outer chamber. After the heat from the reaction has been absorbed by the food, the user can enjoy a hot meal or drink. (Kim Severson, Taking the Heat Out of the Kitchen, The NY Times, May 11, 2005). However, the technology is not yet common, largely due to the expense of the cans and problems with uneven heating of their contents. The Wolfgang Puck coffee was recalled due to complaints that the cans were too hot or cold, or that they otherwise malfunctioned. (Kim Severson & Melanie Warner, Self-Heating Latte Cans Bring Out Lawyers, The NY Times, May 2, 2006). There were allegations that the cans overheated, spurted product from the can, meltdowns, curdled product, and exploded.
As such, there exists an unmet need in the art to generate controlled and/or modulated exothermic reactions.